System and method for electrical energy switching and control in a vehicle

ABSTRACT

This invention discloses a device in a vehicle electrical system which determines the vehicle&#39;s operating conditions and facilitates the transfer of electrical energy between systems of electrical energy sources and their associated electrical loads based on the vehicle operating conditions. The device further determines the operating conditions of the systems of electrical energy sources and their associated electrical loads and facilitates the transfer of electrical energy between them in accordance with said operating conditions.

CROSS REFERENCE TO RELATED APPLICATIONS

The present patent application is a division of a non-provisional patentapplication entitled “System and Method for Electrical Energy Switchingand Control in a Vehicle,” filed Jun. 14, 2004 now U.S. Pat. No.7,202,574, as U.S. patent application Ser. No. 10/867,499 by the sameinventors. This patent application claims the benefit of the filing dateof the cited non-provisional patent application according to thestatutes and rules governing non-provisional patent applications,particularly 35 USC §§120, 121, and 37 CFR §1.78. The specification anddrawings of the cited non-provisional patent application arespecifically incorporated herein by reference.

COPYRIGHT

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The owner has no objection tothe facsimile reproduction by anyone of the patent disclosure, as itappears in the Patent and Trademark Office files or records, butotherwise reserves all copyright rights whatsoever.

FIELD OF INVENTION

This invention is related to electrical systems comprising two or morestored energy sources. In particular, this invention relates to adevice, comprising a system and method, which controllably selects themost optimal energy source available in the electrical system.

BACKGROUND

The present invention relates to electrical systems which compriseelectrical loads, various stored energy sources, and one or moreelectrical energy supplying means such as a generator. Morespecifically, the present invention focuses on a system and method whichmay be utilized in electrical networks, such as a vehicle electricalsystem, where the stored energy sources are controllably configured insuch a manner as to facilitate the transfer of maximum availableelectrical energy in the electrical network to the associated electricalloads in order to satisfy the operating condition requirements.Additionally, the device is configured to controllably transferelectrical energy from a first electrical energy source to one or moreelectrical energy sources and their respective electrical loads in theelectrical system corresponding to the operating condition and in such away as to avoid overloading or otherwise detrimentally affecting saidfirst electrical energy source.

Electrical systems are typically comprised of a generator, electricalloads, and a stored energy source. The stored energy sources functionduring the time when the generator is not operating, so as to providethe required electrical energy to the electrical loads. For example in avehicle electrical system an operating condition may require agenerator, which transforms mechanical energy into electrical energy, tosupply electrical energy when the vehicle engine is operating, and oneor more stored energy sources, such as a battery, to supply electricalenergy during the periods when the vehicle engine is not operating.Another example is where a hybrid vehicle operating condition mayrequire its on-board generator to recharge its depleted batteries inaddition to providing electrical energy to various electrical deviceswhile the vehicle mechanical engine is operating, and its batteries toprovide electrical energy during the periods when the vehicle'smechanical engine is turned off and the vehicle electrical engine isemployed to propel and operate the vehicle.

Such traditional electrical systems ordinarily comprise a main and anauxiliary system of stored energy sources. Both the main and auxiliarysystems may further be comprised of a series of stored energy sources.For instance, in certain vehicles, the electrical system is configuredsuch that there is a main stored energy source which supplies electricalenergy to main electrical loads during engine startup and whenever thegenerator is not operating but there is an auxiliary stored energysource which provides electrical energy to the auxiliary electricalloads. The main and auxiliary systems are connected to the electricalsystem in a parallel configuration and may contain switchable means toprovide isolation or interconnection of any source of electrical energyto the respective electrical loads.

In such electrical systems the main and auxiliary systems areelectrically isolated from each other in a unidirectional manner,meaning that the flow of electrical energy can only take place in apre-designated direction, for example from the main system to theauxiliary system or vise versa. This is done so a single generator mayrecharge main and auxiliary batteries simultaneously, but the batteriesare unable to discharge into each other. Ordinarily, this isaccomplished by incorporating an isolation diode between the generatorand each stored energy source.

A common design of vehicle electrical systems is such that the mainbattery system provides electrical energy to the engine starter to startthe engine, and the auxiliary system provides electrical energy to theelectrical loads while the vehicle's engine is not operating. In theevent that the main system is depleted or otherwise defective, theauxiliary system is incapable of transferring energy to the main systemto enable engine cranking unless a manual switch or relay is provided.Similarly, if the auxiliary system has exhausted its energy and therestill remains a critical need to provide electrical energy to theelectrical loads, the main system is incapable of transferring itsenergy to the auxiliary system unless a manual switch or relay isprovided. Either case of manual switching requires consideration of thecircuit effect when inserting a high energy source into an electriccircuit that contains a very low source impedance inherent to adischarged battery or a possible short circuit that may have causedbattery discharge. This generally leads to a switching means thatdisconnects or isolates the depleted stored energy source that is beingreplaced by the one with the higher energy. This still does notadequately address the case of a short circuit that may have caused theinitial battery discharge.

Although various systems have been proposed which touch upon someaspects of the above problems, they do not provide solutions to theexisting limitations in electrical energy transfer between systems ofstored energy sources, generators, and loads. For example, Renehan, U.S.Pat. No. 6,215,277 discloses an electrical charging system which iscapable of charging two sets of stored energy sources at differentvoltages, but does not address bi-directional electrical energy transferbetween these sources which is the subject of the present invention. InLambert, U.S. Pat. No. 5,162,720, the concept of the invention is toprovide means for connecting the engine battery, the auxiliary battery,and the supplemental electric current source, and for permittingunidirectional current flow to the engine battery from the supplementalelectric current source while the vehicle engine is not operating. Thepresent invention does not require an operational distinction betweenauxiliary battery and engine battery, and furthermore, the flow ofelectrical energy from the stored energy sources may occur in eitherdirection. The Hoinsky patent, U.S. Pat. No. 4,090,122 discloses avehicle electrical system which includes a high capacity storage batteryin addition to the standard vehicle battery to be utilized duringperiods when the vehicle is at rest, but it does not address electricalenergy management between such stored energy sources. Consequently,there is a need for an electrical energy source controller thatcontrollably permits electrical isolation between stored energy sourcesin an electrical system while allowing bidirectional energy transferbetween them. Furthermore, the present invention is capable oftransferring the maximum electrical energy in the electrical system tothe stored energy sources and their associated electrical loads inresponse to the vehicle operating condition.

In modern vehicle designs an electrical energy source may take onvarious forms. Mechanical, chemical, and solar energy, among others, maybe converted into electrical energy for consumption by vehicleelectrical loads. For instance, in a motor vehicle, an electrical energysource usually takes on the form of a generator where mechanical energyis converted into electrical energy. The electrical energy source of asolar-powered vehicle, for example, converts solar energy intoelectrical energy. Additionally, the electrical energy source is alsoresponsible to provide and maintain the necessary electrical energy inthe other electrical energy sources in the system. The first task, i.e.providing electrical energy to the electrical loads, is ordinarily morecritical than the second. Modem vehicles rely heavily on their on-boardelectrical devices. Any disruption in the transfer of energy to suchdevices may lead to an inoperable vehicle. For instance, acomputer-controlled fuel injection system must be operational for theengine to continue operating. A first electrical energy source providingelectrical energy to such loads must not be overloaded or otherwisedetrimentally affected by the demand of electrical energy from otherelectrical energy sources or low priority loads. The other electricalenergy sources must be disconnected if they become a source of overloadfor said first electrical energy source. Furthermore, it is desirable tomonitor said first electrical energy source such as a generator andextract electrical energy from it whenever it is possible to do sowithout causing an overload. Therefore, there is a need for anelectrical energy source controller which monitors electrical energysources in a vehicle electrical system and controllably extractselectrical energy from a first electrical energy source to one or moreelectrical energy sources and their associated electrical loads based onan operating condition requirement.

SUMMARY

The present invention discloses a system and method that permitstransfer of electrical energy between systems of electrical energysources and their associated electrical loads based on an operatingcondition requirement. Additionally, the system is capable ofcontrollably transferring electrical energy between a first electricalenergy source and one or more electrical energy sources and theirassociated electrical loads consistent with the operating conditionrequirement and in such a way as to avoid overloading or otherwisedetrimentally affecting said first electrical energy source. Preferably,the system is configured such that systems of electrical energy sourcesand their respective electrical loads may become completely isolatedwhen an operating condition indicates that no electrical energy sourceis available to share its electrical energy with any other electricalenergy source and or electrical load. Preferably, the system is furtherconfigured such that when an operating condition makes a firstelectrical energy source available, electrical energy is extracted andtransferred from said first electrical energy source to other electricalenergy sources and their associated electrical loads in such a way as toprevent overloading or otherwise detrimentally affecting said firstelectrical energy source.

In one aspect, a system is disclosed comprising two or more electricalenergy sources and a control device connected to and in communicationwith said electrical energy sources and a vehicle electrical system. Thecontrol device is configured to determine an operating condition of thevehicle and to employ an appropriate number of electrical energy sourcesto satisfy a requirement set by the operating condition. Preferably, thesystem is configured such that the control device includes means forsensing or receiving a signal from the vehicle electrical system todetermine a vehicle operating condition. Such signals may containinformation as to the status of the vehicle ignition switch, frequencyof an alternating current of a generator in the vehicle, or a messagefrom the vehicle computer network respecting priorities of electricalenergy sources and electrical loads.

In another aspect, a system is disclosed comprising two or moreelectrical energy sources and a control device connected to and incommunication with said electrical energy sources and a vehicleelectrical system. The control device is configured to determine anoperating condition of the vehicle and to employ an appropriate numberof electrical energy sources to satisfy a requirement set by theoperating condition. Preferably, the system is configured such that thecontrol device includes means for sensing voltages, an energy level, ora rate of deliverable energy of the electrical energy sources, to employan appropriate number of electrical energy sources.

In another aspect, a system is disclosed comprising two or moreelectrical energy sources and a control device connected to and incommunication with said electrical energy sources and a vehicleelectrical system. The control device is configured to determine anoperating condition of the vehicle and to employ an appropriate numberof electrical energy sources to satisfy a requirement set by theoperating condition. Preferably, the system is configured such that thecontrol device includes means to disconnect an electrical energy sourcein order to satisfy the requirements prescribed by the vehicle operatingcondition. A decision to disconnect an electrical energy source may bebased on a time period during which the vehicle engine is turned off, oron a level of priority associated with said electrical energy source.

In another aspect, a system is disclosed comprising two or moreelectrical energy sources and a control device connected to and incommunication with said electrical energy sources and a vehicleelectrical system. The control device is configured to determine anoperating condition of a first electrical energy source and selectivelyto connect or disconnect a second electrical energy source with saidfirst electrical energy source corresponding to the operating condition.Preferably, the system is configured such that the control deviceincludes means for sensing a signal from the vehicle electrical systemrespecting the status of said first electrical energy source todetermine its operating condition. Such signals may contain informationas to the energy level of said first electrical energy source or amessage from the vehicle computer network respecting the availableenergy that may be extracted from said first electrical energy sourcewithout overloading or detrimentally affecting same.

In another aspect, a system is disclosed comprising two or moreelectrical energy sources and a control device connected to and incommunication with said electrical energy sources and a vehicleelectrical system. The control device is configured to determine anoperating condition of a first electrical energy source and selectivelyto connect or disconnect a second electrical energy source with saidfirst electrical energy source corresponding to the operating condition.Preferably, the system is configured such that the control devicedisconnects a second electrical energy source with said first electricalenergy source when the energy level of the latter falls below athreshold value, and connects the second electrical energy source withsaid first electrical energy source when the energy level of the latterrises above a threshold value.

In another aspect, a system is disclosed comprising two or moreelectrical energy sources and a control device connected to and incommunication with said electrical energy sources and a vehicleelectrical system. The control device is configured to determine anoperating condition of a first electrical energy source and selectivelyto connect or disconnect a second electrical energy source with saidfirst electrical energy source corresponding to the operating condition.Preferably, the system is configured such that the control deviceconnects and disconnects a second electrical energy source with saidfirst electrical energy source in such a way as to regulate the transferof energy between the first electrical energy source and the secondelectrical energy source until a threshold value is attained.

In one aspect, a method is disclosed comprising determining an operatingcondition of a vehicle and employing an appropriate number of electricalenergy sources to satisfy the operating condition requirements.Preferably, the method includes sensing or receiving a signal from thevehicle electrical system to determine a vehicle operating condition.Such signals may contain information as to the status of the vehicleignition switch, frequency of an alternating current of a generator inthe vehicle, or a message from the vehicle computer network respectingpriorities of electrical energy sources and electrical loads.

In another aspect, a method is disclosed comprising determining anoperating condition of a vehicle and employing an appropriate number ofelectrical energy sources to satisfy the operating conditionrequirements. Preferably, the method includes sensing an energy level,or a rate of deliverable energy of the electrical energy sources, toemploy an appropriate number of electrical energy sources.

In another aspect, a method is disclosed comprising determining anoperating condition of a first electrical energy source and selectivelyconnecting or disconnecting a second electrical energy source with thefirst electrical energy source which corresponds to the operatingcondition. Preferably, the method includes sensing a signal from thevehicle electrical system respecting the status of said first electricalenergy source to determine its operating condition. Such signals maycontain information as to the energy level of said first electricalenergy source or a message from the vehicle computer network respectingthe available energy that may be extracted from said first electricalenergy source without overloading or detrimentally affecting same.

In another aspect, a method is disclosed comprising determining anoperating condition of a first electrical energy source and selectivelyconnecting or disconnecting a second electrical energy source with thefirst electrical energy source which corresponds to the operatingcondition. Preferably, the method includes disconnecting a secondelectrical energy source with said first electrical energy source whenthe energy level of the latter falls below a threshold value, andconnecting the second electrical energy source with said firstelectrical energy source when the energy level of the latter rises abovea threshold value.

In another aspect, a method is disclosed comprising determining anoperating condition of a first electrical energy source and selectivelyconnecting or disconnecting a second electrical energy source with thefirst electrical energy source which corresponds to the operatingcondition. Preferably, the method includes connecting and disconnectinga first electrical energy source to said second electrical energy sourcein such a way as to regulate the transfer of energy between the firstelectrical energy source and the second electrical energy source until athreshold value is attained.

The following claims define the present invention. The foregoingexplanations, descriptions, illustrations, examples, and discussionsregarding this invention have been set forth to demonstrate the utilityand novelty of this invention and are by no means restrictive of itsscope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a vehicle system according to apreferred embodiment.

FIG. 2 is a schematic of one preferred Electrical Energy SourceController for use in the vehicle electric system of FIG. 1.

FIG. 3 is a flow chart illustrating preferred methods of controllingelectrical energy sources in the electrical system of FIG. 1.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 depicts a block diagram of a vehicle electrical system 10including a preferred embodiment of the Electrical Energy SourceController (EESC) 12. The vehicle electrical system 10 further comprisestwo electrical energy sources at 14 and 16. Electrical energy sourcesmay include batteries, capacitors, generators, a commercial power sourceoutlet, or any other source of electrical energy. System 10 furtherincludes electrical loads 18 and 20. EESC 12 includes an input senseline 22 which is connected to the vehicle ignition switch for thepurpose of determining a vehicle operating condition. EESC 12 furtherincludes an input sense line 24 which is connected to a generator 30where EESC 12 receives a signal in order to determine generatoroperating condition. Although in this embodiment generator 30 isutilized to provide EESC 12 information for determination of thegenerator or vehicle engine operating condition, said generator may betreated as a third electrical energy source in the vehicle electricalsystem. It is contemplated that in other embodiments, sense lines 22 or24 may be connected to the vehicle computer network via a Data I/O port29 where EESC 12 receives information as to the vehicle operatingcondition. Input sense lines 26 and 28 are connected to electricalenergy sources 14 and 16 where EESC 12 receives information as to thestatus of said electrical energy sources. It is also contemplated thatin other embodiments, sense lines 26 or 28 may be connected to thevehicle computer network via a Data I/O port 29 where EESC 12 receivesinformation as to the status of the electrical energy sources for thepurpose of employing an appropriate number of them to satisfy thevehicle operating condition. Yet in other embodiments, instead of inputsense lines 22, 24, 26, and 28, a Data I/O port 29 may be connected tothe vehicle computer network where EESC 12 receives sufficientinformation to determine the vehicle operating condition and the statusof the electrical energy sources so that it may utilize an appropriatenumber of such sources to meet the requirement prescribed by theoperating condition. Embedded in EESC 12 are two switches at 32 and 34,utilized by EESC 12 to engage an appropriate number of electrical energysources 14 and 16, to meet the requirement of the operating condition.Said switches also serve as a means to isolate individual electricalenergy source from other electrical energy sources and/or electricalloads. The switches are controllable to regulate the average currentconducted by the switch. In other embodiments, multiple switches may beutilized effectively to isolate all electrical energy sources andelectrical loads from one another. Diodes 36 and 38 are included toisolate individual electrical energy source from other electrical energysources and/or electrical loads.

EESC 12 is connected to and in communication with the vehicle electricalsystem via input sense lines 22 and 24. These input sense lines provideEESC 12 means for ascertaining a myriad of operating conditions whichmay exist throughout the vehicle operating life. These operatingconditions include periods when the vehicle engine is at rest, about tostart, or operating. Although it is not feasible to provide anexhaustive list of different operating conditions, situations where thevehicle primary source of energy is mechanical, electrical, or solar,may be considered to be among them.

In one embodiment, input sense line 22 is connected to the vehicleignition switch. If there is a signal present on line 22, it isindicative that the vehicle is either about to start or is operating.Input sense line 24 receives a signal from generator 30 which indicatesthe status of said generator. If there is an AC ripple present on line24, it is indicative that the vehicle mechanical engine is operating andgenerator 30 is properly converting mechanical energy into electricalenergy.

In one embodiment, both signals on input sense lines 22 and 24 aremonitored and a determination is made as to the vehicle operatingcondition. If both input sense lines 22 and 24 are devoid of signals,EESC 12 interprets this situation as a vehicle at rest. This is criticalfor situations where EESC 12 must electrically isolate an electricalenergy source to be utilized during engine cranking. If a signal ispresent on line 22, but there is no signal present on line 24, EESC 12interprets the situation as a vehicle that is about to start. This iscritical for devices that are utilized to engage the vehicle mechanicalengine, for instance, a starter motor 40. In this scenario, EESC 12 mayutilize one or a combination of electrical energy sources in the vehicleto provide the starter motor 40 with the maximum available electricalenergy in the system. It is also desirable at this time to inhibitgenerator 30 operation by sending a signal from the Data I/O port 29 toinhibit a signal at Regulator E terminal. If both input sense lines 22and 24 carry signals, then EESC 12 interprets the situation as a vehiclethat is operating. This is critical for electrical energy sources, suchas a generator, which are capable of converting mechanical energy intoelectrical energy. In this instance, EESC 12 may make a determinationthat the generator may be utilized as a first electrical energy sourceto be connected with a second electrical energy source to selectivelyconnect or disconnect the latter with the first in response to saidoperating condition.

In one embodiment, one or both input sense lines 22 and 24 may beconnected to the vehicle computer network via a Data I/O port 29 whereEESC 12 may receive information as to the vehicle and/or electricalenergy sources operating conditions. In one scenario, the vehiclecomputer network may transmit information as to status and priorities ofelectrical loads and/or electrical energy sources. EESC 12 may obtainother critical information such as vehicle primary source of energy viasaid Data I/O port. This information may be utilized by EESC 12 tosatisfy the requirements commensurate with the vehicle operatingconditions.

EESC 12 is connected to and in communication with the electrical energysources 14 and 16 via input sense lines 26 and 28 to determine thestatus of said electrical energy sources. The signals on these inputsense lines include, among others, available electrical energy ordeliverable rate of energy.

In one embodiment, input sense lines 26 and 28 may carry signalsproportional to the available energy in the electrical energy sources 14and 16. An operating condition may require that an electrical energysource with the highest electrical energy be electrically isolated fromthe electrical system to be used during a particular event, such as topower starter motor 40 during a vehicle startup. Accordingly, EESC 12manipulates the corresponding switch from switches 32 and 34 to anopen-circuit position to accomplish the task. As stated above, a DataI/O port 29 may be connected to the vehicle computer network for EESC 12to receive information regarding the available energy in the electricalenergy sources 14 and 16.

In one embodiment, input sense lines 26 and 28 may carry signalsproportional to the rate of deliverable electrical energy from theelectrical energy sources 14 and 16. An operating condition may requirethat an electrical energy source with the highest deliverable rate ofelectrical energy be utilized to replenish a depleted electrical energy,such is the case when a battery may be utilized to recharge a depletedcapacitor. As stated above, a Data I/O port 29 may be connected to thevehicle computer network for EESC 12 to receive information regardingthe deliverable rate of energy from the electrical energy sources 14 and16.

EESC 12 comprises two switches 32 and 34 to connect or disconnect anelectrical energy source with another electrical energy source or anelectrical load in order to satisfy an operating condition requirement.These switches also serve to isolate an electrical energy source or anelectrical load from another electrical energy source or electricalload. These switches may be activated individually or in combination sothat an appropriate number of electrical energy sources are employed tosatisfy the operating condition. Additionally, switches 32 or 34 may beactivated so that a first electrical energy source, selectively, may beconnected or disconnected with the other electrical energy source sothat the former may recharge the latter based on the operatingcondition.

In one embodiment, EESC 12 may set switch 34 on closed-circuit positionso that electrical energy source 14 may supply electrical energy toelectrical load 20 in addition to the amount being supplied byelectrical energy source 16. This situation may occur when the vehicleis at rest and the operating condition, as determined above, dictatethat electrical energy source 14 be utilized to satisfy the powerrequirement of load 20.

In one embodiment, EESC 12 may set switch 32 on closed-circuit positionso that electrical energy source 16 may supply electrical energy toelectrical load, namely starter motor 40, when the vehicle is about tostart. As mentioned above, once the operating condition has beendetermined, EESC 12 examines the status of the electrical energy sources14 and 16 and, activates switches 32 and/or 34 to meet the operatingcondition. If both electrical energy sources are fully charged, EESC 12activates switches 32 and 34 so that both electrical energy sourcessupply electrical energy to the starter motor 40.

In one embodiment, EESC 12 may activate both switches 32 and/or 34,selectively connecting or disconnecting an electrical energy source 14or 16 with generator 30, when the vehicle is operating. In thisembodiment, generator 30 is utilized as a third electrical energy sourcein the vehicle electrical system. For instance, upon verification of theexistence of an AC ripple on input sense line 24, EESC 12 becomes awarethat generator 30 may be an electrical energy source candidate forreplenishing electrical energy sources 14 and 16 with electrical energy.Upon a determination of the operating condition of generator 30, namelywhether excess energy is available, EESC 12 activates sequentially or inconcert, switches 32 and/or 34 to recharge electrical energy sources 14and 16 according to the operating condition of generator 30.

In one embodiment, electrical energy source 14 may be a battery,electrical energy source 16 may be a capacitor, and a third electricalenergy source 30 may be one that converts solar energy into electricalenergy. Input sense line 22 may be connected to a sensor where EESC 12obtains information that solar energy may rapidly become unavailable.Due to the time limitation and the fact that capacitors may be rechargedmuch faster than batteries, EESC 12 sets switch 32 on open-circuitposition to disconnect the electrical energy source 14 and electricalloads 18 and 36 from the vehicle electrical system, and selectivelyconnects or disconnects, via switch 34, the capacitor 16 with said thirdsolar powered electrical energy source to replenish capacitor 16.

FIG. 2 illustrates an embodiment of EESC 12 as a control deviceutilizing processor 44. In this embodiment, substantial part of theEESC's functions may be controlled solely by processor module 44. Inother embodiments, multiple processors of the type such as the processormodule 44, or other types, may be utilized to operate concurrently inparallel or series configurations to process and control the EESCfunctions. EESC 12 is not limited to digital processors. Analog or otherdiscrete or integrated circuit components may be arranged to enable theEESC to perform the same functions as those performed by the digitalprocessor. The processor module 44 preferably comprises amicroprocessor, a processor clock, and a power supply. In one preferredembodiment, the microprocessor is a 68C08 processor having internalflash memory available from Motorola, Inc. of Schaumburg, Ill. Theinternal clock may be a crystal-type oscillator or other oscillatormechanism known to those practiced in the art, and the power supply maybe a discrete or integrated circuit configured to supply the processormodule 44 with appropriate DC voltage. It is contemplated that theprocessor module may be a combination of individual discrete or separateintegrated circuits packaged in a single housing or it may be fabricatedin a single integrated circuit.

In one embodiment, processor module 44 is in communication with thevehicle electrical system via input sense lines 22 in order to determinethe vehicle operating conditions. In particular, processor module 44monitors the vehicle ignition switch, via input sense line 22 todetermine whether it has been activated. When the vehicle ignitionswitch is set on on-position, a voltage is present on line 22. Thevoltage level on the ignition line 22 is further conditioned forprocessor consumption. Processor 44 monitors line 22 and upon detectionof the voltage, it determines that the vehicle is either about to startor operating. Although in this embodiment, processor 44 monitors avoltage level on line 22, in other embodiments, line 22 may be connectedto the vehicle computer network via a Data I/O port 29 where processormodule 44 receives data which, among others, contains informationregarding the vehicle operating condition.

In one embodiment, processor 44 is in communication with the vehicleelectrical system via input sense line 24 in order to determine thevehicle operating conditions. Specifically, input sense line 24 may beconnected to the output of generator 30 where processor module 44monitors the ripple frequency of the generator signal to compute afrequency which may be used to ascertain whether the vehicle is about tostart or operating. In conjunction with input sense line 22, processormodule 44 is capable of determining if the vehicle is at rest, about tostart, or operating as discussed above. In other embodiments, processormodule 44 may be connected to the vehicle computer network to determinethe vehicle operating condition, via a Data I/O port 29.

In one embodiment, processor module 44 is in communication withelectrical energy sources in the vehicle electrical system through inputsense lines 26 and 28. Processor module 44 receives signals that containinformation regarding the status and operating condition of electricalenergy sources 14 and 16. Specifically, signals on lines 26 and 28 areconditioned for use by processor module 44 in form of voltage levels.Processor module 44 uses these signals to ascertain the voltage levelsand rate of voltage level variations in order to decide which electricalenergy sources should be employed to satisfy the operating condition.

In one embodiment, processor module 44 may examine the voltage level onlines 28 and 26 and compare them with a prescribed value. One or bothelectrical energy sources 14 and 16 may be utilized by activatingswitches 32 and 34 to supply electrical energy if the correspondingvoltage level is above the prescribed value.

In one embodiment, processor module 44 may compare the rate at which theaverage voltage of electrical energy sources 14 and 16 varies withrespect to time, while they are either being recharged or depleted. Suchcomputations may be used to determine the rate of deliverable electricalenergy so that processor module 44 may employ an appropriate number ofelectrical energy sources to meet the operating condition. Other meansfor performing such computations may be utilized such that input senselines 26 and 28 carry information directly proportional to the rate ofdeliverable electrical energy. In other embodiments, processor module 44may be connected to the vehicle computer network to receive informationregarding the voltage level, rate of delivery, or priority level ofindividual electrical energy sources 14 and 16, over a Data I/O port 29to evaluate the status and operating condition of said sources.

In one embodiment, processor module 44 utilizes switch modules 32 and 34to employ an appropriate number of electrical energy sources thatsatisfies the vehicle operating condition. Two bi-directionalsemiconductor switching modules BSSMs 32 and 34 are embedded in EESC 12in order to controllably connect and disconnect electrical energysources 14 and 16 from the vehicle electrical system. The BSSMs aredriven by opto-couplers 46 and 48 which are in turn controlled byprocessor 44. Opto-couplers 44 and 48 are utilized to isolate processor44 from circuit noise.

In one embodiment, processor modules 44 closes switch 34 so thatelectrical energy source 14 may supply electrical energy to electricalenergy source 16 and electrical load 20, in response to the operatingcondition as discussed above.

In another embodiment, processor 44 closes switch 32 so that electricalenergy source 16 may supply electrical energy to electrical energysource 16 and electrical loads 18 and 40, in response to the operatingcondition as discussed above.

In one embodiment, processor 44 controllably manipulates switches 32and/or 34 to selectively connect and disconnect electrical energysources 14 and 16 with generator 30, so that the latter may recharge theformer, in response to the operating condition as discussed above.

In one embodiment, processor module 44 may be connected to and incontrol of visual indicators such as light emitting diodes 50 and 52which transmit information regarding the status of electrical energysources 14,16, and 30, electrical loads 18, 20 and 40, vehicle operatingconditions, or diagnostic information. These visual displays may beoperated in the same manner as the warning light in automobiles, or theymay be operated to display certain patterns, or they may be operated todisplay text, any which method may provide detailed information to thevehicle operator as to the status and operating conditions of variouscomponents.

Utilizing system 10 illustrated above, one embodiment of the operationof EESC 12 is now described. EESC 12 monitors the vehicle operatingcondition utilizing input sense lines 22 and 24. Input sense line isconnected to the vehicle ignition switch and input sense line 24 isconnected to the output of generator 30. Absence of signal on theselines indicates that vehicle is at rest. EESC 12 accordingly sets bothswitches 32 and 34 on open-circuit position so that electrical energysources 14, 16, and 30 and their corresponding electrical loads becomeelectrically isolated from one another.

In one situation, electrical energy source 16 may become severelydepleted due to excess use, defect, or short circuit. When the vehicleignition switch is set on off-position and generator 30 is not producingpower, EESC 12 recognizes the absence of a signal on the ignition switchand on the AC output of generator 30 and interprets the operatingcondition as a vehicle that is at rest. EESC 12 then checks the statusof electrical energy sources 14 and 16 utilizing input sense lines 26and 28 and closes switch 32 and 34 to supply electrical load 20 withelectrical energy from both electrical energy sources 14 and 16. In oneembodiment, additional switches and/or diodes may be utilized toelectrically isolate individual electrical energy sources and electricalloads, so that a particular electrical energy source anywhere in theelectrical system may be connected to an electrical load. For example,in FIG. 1, system 10 may be configured so that there are additionalswitches between electrical energy source 14 and electrical loads 18 and40, and electrical energy source 16 and electrical load 20, so thatunder the above vehicle operating condition, EESC 12 may connectelectrical energy source 14 directly to electrical load 20 without theformer sharing electrical energy with any other electrical energy sourceor electrical load.

In one situation, electrical energy source 14 may become severelydepleted due to excess use, defect, or short circuit. When the vehicleignition switch is set on on-position while generator 30 is not yetproducing power, EESC 12 recognizes the presence of a signal on theignition switch and lack of a voltage ripple on the output of generator30 and interprets the operating condition as a vehicle that is ready tobe started. EESC 12 will then check the status of electrical energysources 14 and 16 utilizing input sense lines 26 and 28 and closesswitch 32 and 34 to supply starter motor 40 with electrical energy fromboth electrical energy sources 14 and 16. In one embodiment, additionalswitches and/or diodes may be utilized to electrically isolateindividual electrical energy sources and electrical loads, so that aparticular electrical energy source anywhere in the electrical systemmay be connected to an electrical load. For example, in FIG. 1, system10 may be configured so that there are additional switches betweenelectrical energy source 14 and electrical loads 18 and 40, andelectrical energy source 16 and electrical load 20, so that under theabove vehicle operating condition, EESC 12 may connect electrical energysource 16 directly to electrical load 40 without the former sharingelectrical energy with any other electrical energy source or electricalload.

In one situation, electrical energy sources 14 and 16 are both fullycharged. When the vehicle ignition switch is set on on-position whilegenerator 30 is not yet producing power, EESC 12 recognizes the presenceof a signal on the ignition switch and lack of a signal on the output ofgenerator 30 and interprets the operating condition as a vehicle that isready to be started. EESC 12 then checks the status of electrical energysources 14 and 16 utilizing input sense lines 26 and 28 and closesswitch 32 and 34 to supply starter motor 40 with electrical energy fromboth electrical energy sources 14 and 16. This is desirable especiallyin low temperatures because starter motor 40 may draw electrical energyfrom both electrical energy sources 14 and 16.

In one situation, electrical energy sources 14 and/or 16 may becomeseverely depleted due to excess use, defect, or short circuit. When thevehicle ignition switch is set on on-position while generator 30 isproducing power, EESC 12 recognizes the presence of a signal on theignition switch and a ripple frequency on the output of generator 30 andinterprets the operating condition as a vehicle that is operating. EESC12 then checks the status of electrical energy sources 14 and 16utilizing input sense lines 26 and 28 and controllably closes switch 32and 34 sequentially or in concert, selectively connecting electricalenergy sources 14 and 16 with electrical energy source 30, to replenishthe former with energy from the latter.

FIG. 3 illustrates an example of one method of implementing the EESC 12.Upon power up at 54, EESC 12 monitors the status of the vehicle ignitionswitch. If the switch is on off-position, EESC 12 sets switches 32 and34 on off-position, at 56 and 58, so that electrical energy sources andtheir corresponding electrical loads become isolated. If the vehicleignition switch is set on on-position, at 60, EESC 12 continues to scaninput sense lines 24, 26, and 28 to determine the status and operatingconditions of the generator 30 and electrical energy sources 14 and 16,at 62 respectively.

Upon obtaining the voltage levels of said generator and electricalenergy sources, EESC 12 compares the voltage levels of electrical energysources 14 and 16 with a threshold value at 64. If the voltage level ofelectrical energy source 14 is greater and that of 16 is less than thethreshold value, EESC 12 sets switch 32 on on-position and switch 34 onoff-position and further setting the light emitting diode (LED) clusters50 and 52 such that the LED corresponding to switch 32 is turned on toilluminate a green light and LED corresponding to switch 34 is turnedoff, at 66.

EESC 12 continues with monitoring the voltage level of electrical energysource 16 at 68, and selectively connects and disconnects generator 30with electrical energy source 16, at 70, and continues steps 68 and 70until the voltage level of electrical energy source 16 reaches a valueabove a threshold value, at 72. Once this condition is satisfied, EESC12 closes switch 34 and turns on the LED corresponding to switch 34 toilluminate a green light, at 74. EESC 12 then continues executing steps78 through 90 which are discussed below.

If the voltage level of electrical energy source 14 is not greater andthat of 16 is less than the threshold value, EESC 12 sets switches 32and 34 on on-position and further setting the light emitting diodeclusters 50 and 52 such that each LED corresponding to switches 32 and34 is turned on to illuminate a green light, at 76.

EESC 12 continues to scan input sense lines 24, 26, and 28 to determinethe status and operating conditions of the generator 30 and electricalenergy sources 14 and 16, at 78 respectively. EESC 12 continues bydetermining two reference voltages, VS1 and VS2, corresponding to thedifferences between electrical energy sources 14 and 16, and generator30, respectively at 80. If VS1 is greater and VS2 is less than aprescribed value, for example 0.3 Volts at 82, EESC 12 turns on LEDclusters 50 and 52 such that each LED corresponding to switches 32 and34 is turned on to illuminate a green light at 84.

EESC 12 continues to execute steps 78 through 84 until reference voltageVS1 is above the threshold at 86, at which time the LED corresponding toswitch 32 is turned on to illuminate a red light at 88. EESC 12continues to execute steps 78 through 88 until reference voltage VS1 isless than and VS2 is greater than the threshold value, at which timeEESC 12 turns on the LED corresponding to switch 34 to illuminate a redlight at 90. EESC 12 continues to execute steps 78 through 90 accordingto various vehicle operating conditions.

The forgoing discloses a system and method for controlling electricalenergy sources in a vehicle. It describes two fundamental functions ofthe invention, namely a system and method which employs an appropriatenumber of electrical energy sources to satisfy the vehicle operatingconditions. Secondly, it describes a system and method which maintainsstandby electrical energy sources in an optimum state of readiness.

The first function addresses the problem of the existing systems wheremultiple electrical energy sources are employed based on a presupposedvehicle operating condition, incapable of adapting itself to changes inthe vehicle operating condition. This invention constantly monitors thevehicle electrical system at all times and appropriately engages theelectrical energy sources to satisfy the vehicle operating conditions.

The second function addresses the problem of extracting energy from anelectrical energy source and distributing it among other electricalenergy sources without detrimental effects on the former. This task isachieved by monitoring the operating conditions of all the electricalenergy sources in the vehicle and distributing electrical energy fromthose that are ready to supply it to those that are ready to receive it.

The examples and illustrations have been used to assist the reader withunderstanding this invention and not intended to limit the scope of it.It is the following claims, including all equivalents, which areintended to define the scope of this invention.

1. A system for controlling electrical energy sources in a vehicle,comprising; (a) two or more electrical energy sources; (b) a controldevice connected to and in communication with said electrical energysources; said control device determining an operating condition of afirst electrical energy source and selectively connecting ordisconnecting a second electrical energy source without detrimentallyaffecting said operating condition.
 2. The system of claim 1, wherein(a) comprises a generator.
 3. The system of claim 1, wherein (b)comprises means for sensing an energy level of the first electricalenergy source to determine said operating condition.
 4. The system ofclaim 3, wherein the control device detects a voltage level of saidfirst electrical energy source via said sensing means.
 5. The system ofclaim 3, wherein the control device connects the second electricalenergy source with said first electrical energy source when said energylevel is above a threshold value.
 6. The system of claim 3, wherein thecontrol device disconnects the second electrical energy source with saidfirst electrical energy source when said energy level falls below athreshold value.
 7. The system of claim 1, wherein the control deviceselectively connecting or disconnecting two or more electrical energysources.
 8. A system for controlling electrical energy sources in avehicle, comprising; (a) two or more electrical energy sources; and (b)means for controlling said electrical energy sources; said means forcontrolling determining an operating condition of a first electricalenergy source and selectively connecting or disconnecting a secondelectrical energy source without detrimentally affecting said operatingcondition.
 9. A control device for controlling two or more electricalenergy sources in a vehicle, comprising; means for switching anelectrical energy source; and a processor including a programming codeoperable on the processor; said processor determining an operatingcondition of a first electrical energy source and selectively connectingor disconnecting a second electrical energy source with said firstelectrical energy source via said switching means without detrimentallyaffecting said operating condition.
 10. The control device of claim 9,wherein said processor comprises an input sense line coupled with saidfirst electrical energy source to determine said operating condition.11. The control device of claim 10, wherein said processor detects anenergy level of said first electrical energy source via said input senseline.
 12. The control device of claim 11, wherein said processorconnects the second electrical energy source with said first electricalenergy source when said energy level is above a threshold value.
 13. Thecontrol device of claim 11, wherein said processor disconnects thesecond electrical energy source with said first electrical energy sourcewhen said energy level falls below a threshold value.
 14. The controldevice of claim 9, wherein said processor selectively connecting ordisconnecting two or more electrical energy sources.
 15. A controldevice for controlling two or more electrical energy sources in avehicle, comprising; means for switching an electrical energy source;and processing means for determining an operating condition of a firstelectrical energy source; said processing means selectively connectingor disconnecting a second electrical energy source with said firstelectrical energy source via said switching means without detrimentallyaffecting said operating condition.
 16. A method for controlling two ormore electrical energy sources in a vehicle, comprising; (a) determiningan operating condition of a first electrical energy source; and (b)selectively connecting or disconnecting a second electrical energysource with said first electrical energy source without detrimentallyaffecting said operating condition.
 17. The method of claim 16, wherein(a) comprises sensing an energy level of said first electrical energysource to determine said operating condition.
 18. The method of claim17, wherein (b) comprises connecting the second electrical energy sourcewith said first electrical energy source when said energy level is abovea threshold value.
 19. The method of claim 17, wherein (b) comprisesdisconnecting the second electrical energy source with said firstelectrical energy source when said energy level falls below a thresholdvalue.
 20. The method of claim 16, wherein (b) comprises selectivelyconnecting or disconnecting two or more electrical energy sources.